In this lesson,
we're going to cover cable distribution systems.
Now, a cable distribution system is an organized system
to connect the network's backbone
in the main distribution frame
to the intermediate distribution frame,
and then finally to the end user's wall jacks.
When we design a cable distribution system,
it should be hierarchal in nature
so that each cable run is logically placed safely,
securely, and functionally inside of our buildings.
When fully installed,
there are a lot of different components
that make up our cable distribution systems,
including the demarcation point,
the main distribution frame,
the intermediate distribution frame,
the racks, the patch panels,
and the fiber distribution panels.
First we have the demarcation point.
The demarcation point is the location
at which the internet service provider's connection
is going to end,
and your network infrastructure
and cabling will actually begin.
This demarcation point signifies the entrance
where your wide area network connection
is actually going to enter your facility.
In most office buildings,
there's a telecommunications closet
that contains a box inside of it,
and this will serve as your demarcation point.
Basically, your internet service provider,
whether you're using a cable company
or a phone company,
is going to be responsible
for making sure the connection works
up until that demarcation point.
Anything that goes wrong after it reaches that box,
which is your demarcation point,
is now your organization's responsibility to fix and repair
because all of those cables are considered
to be part of your own network infrastructure
and cable distribution system.
Most often, this demarcation point
will be located in your main distribution frame.
Your main distribution frame, also known as the MDF,
will serve as your main starting point
for all of your interior cabling
that is going to be distributed throughout your building.
Every other telecommunications closet
you have in your building
is going to reach back into this main distribution frame too.
I like to think about it like a trunk of a tree
where all the smaller branches
are going to go out to form smaller distribution frames
that we call intermediate distribution frames or IDFs.
Inside of your main distribution frame,
you're going to find your main point of presence router
and your backbone switch.
This switch is called the backbone
because everything else in the network
will connect back into it.
If you have a small network,
you may only have one 24-port switch
that's going to serve all of your users,
and in that case, that single switch
is going to be considered your backbone switch.
But if you work for a larger organization
with hundreds or thousands of users,
you're going to need more than one switch.
So you're going to have a backbone switch,
and then you're going to connect smaller edge switches
in each intermediate distribution frame,
and they're going to connect back to your backbone switch
that's located inside of your main distribution frame.
Now to connect the main distribution frame
to the intermediate distribution frames,
we're going to install cable trays
and then we'll run our cables within these trays.
A cable tray is simply a unit or assembly of units
that form a rigid structural system
to securely support the cables and raceways
that are used by your cables
as they're moving across the building.
When we run our cables horizontally,
we're going to do this inside of these cable trays,
and these trays are usually going to be located
up in the drop ceiling or underneath a raised floor
depending on how your building was constructed.
Now, as you move vertically up or down
between the floors of your building,
you're going to run your cables
through a vertical cross-connect.
In general, it's a best practice
to minimize the number of cables
that you have crossing between your floors vertically.
For this reason, we're usually only going to run trunk cables
to connect your main distribution frame
and its backbone switch
out to the intermediate distribution frames
and their edge routers
through those vertical cross-connects.
Inside your distribution frames,
you'll also find one or more racks
that house your network equipment.
These racks are going to be designed
to hold various devices like switches, routers,
patch panels, and servers
to help facilitate efficient space management
and easy access for your ongoing network maintenance.
These racks are typically made out of sturdy materials
to support the weight of the equipment
and may include features like adjustable shelves,
cable management systems, and lockable doors for security.
These racks come in various shapes and sizes,
but the four most common are called 2-post racks,
4-post racks, wall-mounted racks and rack enclosures.
Now, a 2-post rack is designed with two vertical posts,
and it's commonly used for lighter equipment
or for patch panels and network cabling
inside of a telecommunication setup.
A 4-post rack is designed with four vertical posts,
and it offers enhanced stability
and support that makes it ideal
for heavier equipment like servers,
UPS systems and large network hardware.
Wall-mounted racks are space saving solutions
that are used for smaller networking equipment
and are ideal for environments with limited floor space
and for housing peripheral network components.
I also use wall-mounted racks
to host edge switches inside of offices
when an intermediate distribution frame
was not built into the original office designs.
A full cabinet rack,
also known as a rack enclosure
is a fully enclosed rack with sides, doors, and a top,
and this offers us a secure and protected environment
for high-value equipment like servers, networking devices,
and data storage hardware.
If you're using a wall mounted rack or a rack enclosure,
these also have the option to have a lock installed
that can be locked and unlocked using a key
to keep your servers and other equipment safe
and inaccessible to unauthorized people.
Now, inside of our intermediate distribution frames,
we're going to place any equipment
that we need to support the offices and workstations
that are located closest to it.
If you're in a smaller office building,
you're likely only going to have
one intermediate distribution frame located on each floor,
but if you're in a larger building,
you may have multiple intermediate distribution frames
on each of those floors.
If that's the case,
then you're usually going to go
from the main distribution frame
to one of the intermediate distribution frames
on a given floor,
and then that intermediate distribution frame
you just connected to will now serve
as a mini main distribution frame
for the rest of the intermediate distribution frames
on that particular floor.
From each intermediate distribution frame,
you're going to have the cabling
that runs through the cable trays to the individual offices
and down the walls
where they're going to connect to a wall jack.
These wall jacks are normally going to be configured
to accept an RJ-45 jack in most organizations,
but you can also use fiber wall jacks too
if you require them for additional security
or for higher speed applications.
Now in the intermediate distribution frame,
we also have patch panels
that are going to be installed inside of our racks.
The patch panel is a device or unit
featuring a number of jacks for the use of connecting
and routing circuits for monitoring,
interconnecting and testing circuits
in a more convenient and flexible manner.
Basically, a patch panel is really going to be used
to keep your data center or server room better organized
and as well as making it easier for you to move,
add, or change your cable distribution infrastructure
in the future.
In general, a patch panel is going to have two sides.
On the front side,
you're going to find all of your network jacks,
which includes a series of RJ-45 network ports
if you're using a copper cabling based network
for your distribution system.
On the backside,
you're going to find what looks like a 110 punchdown block
so you can punchdown the copper cables
onto that integrated block.
Now, a 110 block is a type of punchdown block
that we use for both voice and data application,
and anytime we're relying on CAT 5
or newer copper-based networks,
we're going to use a 110 block.
Now, the 110 block
includes the use of insulation displacement
contact connectors to terminate the twisted pair of cables
onto the punchdown blocks
and provide adequate spacing between each cable pair
to help prevent crosstalk and electromagnetic interference
when you're using copper cabling
for your high-speed data networks.
When installing cables on the punchdown block,
you're going to use a tool known as a punchdown tool.
This tool comes with a small blade
that's used to push
the twisted pair cable down into the teeth of the block
and then cut off any excess cabling
from that twisted pair.
This punchdown block is going to allow the connectors
on the block to bite into the cable
in order to make the network connection
and then hold that individual copper wire in place.
So why would I want to go through all this trouble
to use a patch panel
instead of just putting an RJ-45 connector
on the end of one of these copper cables
that are coming into our intermediate distribution frame
and plugging that directly
into a switch port on a router or switch?
Well, you could connect the cable directly,
but we don't consider that
to be a best practice in our industry.
Instead, you should always connect
the wall jacks cable to a patch panel.
This allows the patch panel to provide you
with an easy to use network jack on the front side of it.
Then that way you can connect it
to a switch using a patch cable.
You see, patch panels are really cheap and inexpensive,
and so they protect our expensive network components
from damage when we're moving people and cables around
inside of our enterprise networks.
Every time you plug or unplug a cable into a port,
the more wear and tear is going to occur on that port
and eventually that port will fail.
For this reason, I would rather the patch panel fail
than a port on my expensive switch or router.
So I'm going to punchdown the cable
to the back of the patch panel
and then connect a patch cable
to the front jack on that patch panel
and go from port number one
to port number one on the switch.
Now, if I need to move that port to somewhere else,
I just unplug it from port number one on the patch panel
and plug it into the right port
to go to the other office like port number two
or port number three or whatever, and that way,
instead of moving the connection on the switch itself,
I'm only moving it on the patch panel.
Now if I break a patch panel switchboard,
I'll just replace the entire patch panel
because that entire thing is only 50 or $100
instead of having to replace a switch
that might be 5,000 or 10,000 or $20,000
depending on the size and scale of my networking equipment.
Now, in addition to copper patch panels,
which rely on these punchdown blocks,
there's another type of patch panel that we use for fiber,
and these are known as fiber distribution panels.
Now, unlike a copper patch panel,
there's no punchdown on the backside of them.
Instead, these fiber distribution panels
use fiber connectors like SC, LC, ST, and MTRJ
to make their connections.
Both the front and back
of the fiber distribution panel
will usually have the same type of fiber connections
so that the fiber distribution panel
is essentially just a coupler from one fiber cable
being connected on the backside of the panel
to the other fiber cable that's attached
to the front side of the panel.
Then the front side of the fiber distribution panel
has that fiber patch cable that will connect directly
to the switch port on your router or switch.
These fiber distribution panels
can also act as a converter for you
if you need to convert one type
of fiber connection to another.
For example, you might have an SC connector on the backside
and an ST or MTRJ located
on the front side of that fiber distribution panel,
and it will do the conversion for you.
All right, now that we've defined
all the different components,
let's take a quick look at how all this works together
by considering what the cable distribution
from a switch in an intermediate distribution frame
will look like as it moves out to the desktop
of one of our end users.
Now this is important to understand
because when you go to your office tomorrow
and you plug in a new computer
into the wall jack of that network connection,
there's actually a lot that's happening behind the scenes
that the end user is simply never going to see or understand.
So the computer is first going to be connected
to the wall jack using a straight-through patch cable.
This can be a copper patch cable
if you're using something like Cat6A,
or it can be a fiber patch cable
if you're using a fiber-based cable distribution plant.
The wall jack or wall outlet will have a connector on it
like an RJ-45 connector
if you're using copper network cabling.
And on the back of this jack,
there's a punchdown block that terminates the copper cable
and then runs that cable through the walls
up into the ceiling or down into the raised floor,
and then across the cable trays
until it reaches the intermediate distribution frame.
From here, that cable is going to be terminated
into a punchdown block on the back of a patch panel,
and then we're going to use another patch cable
to connect it from the patch panel
to an open port on the edge switch
located inside this intermediate distribution frame.
Now, if I wanted to use fiber instead of copper here,
I certainly could.
We would just replace the switch with a fiber switch,
the patch panel with a fiber distribution panel
and the wall jack with a fiber wall jack.
In either of these cases though,
what we're really doing is taking one long cable
that would otherwise have to go
from the end user's desktop all the way to the switch,
and instead we're breaking it up into multiple pieces
so we have additional flexibility
if we need to move it or repair it later on.
For example, if the cable between the switch
and the patch panel breaks,
I could simply unplug it
and replace it with another patch cable.
If a cable between the wall jack
and the patch panel gets broken,
I can just replace that and then re-punch it down again.
By having lots of places to troubleshoot
or fix the cable at,
it's going to give us more options
to get that network up and running much faster
and much more quickly
than if we had to do an entire new cable run
every time somebody had to move a machine to a new office
where every time a cable got broken somewhere
between the edge switch and the end user.
So remember, your cable distribution system
is made up of several different components,
including the demarcation point,
the main distribution frame,
the intermediate distribution frame,
the racks, the patch panel,
and the fiber distribution panel.
These different components are going to make it easier for us
to support and maintain
our network's cable distribution system
in a more hierarchal and organized manner for the long term.